WASHINGTON - Samuel Alito coasted today toward probable confirmation as the 110th Supreme Court justice, with the only question after 18 hours of grueling Senate interrogation being how many Democrats would support him.

Alito said nothing to undermine his solid support by the Senate's majority Republicans during three days of aggressive questioning by Democrats who challenged his credibility, judicial philosophy and independence.

"I am my own person, with whatever abilities I have and whatever limitations I have," Alito declared as he wrapped up his final public appearance before senators begin voting on his nomination to replace retiring Justice Sandra Day O'Connor.

Democrats contend the former Reagan administration lawyer is likely to swing the court to the right in replacing the centrist O'Connor, who has provided decisive votes on such important issues as abortion, capital punishment and affirmative action.

Judiciary Committee senators will meet next Tuesday to begin debating the 55-year-old federal judge's nomination. Chairman Arlen Specter, R-Pa., had wanted a committee vote then, but Democrats are expected to delay it for a week after that so they can discuss the nomination together first.

Senate Democratic Leader Harry "Reid is urging all Democrats to refrain from committing to a vote either for or against confirmation prior to the caucus next Wednesday," spokesman Jim Manley said.

Delay is not likely to change Alito's support among the Senate's 55 Republicans. GOP senators, both on and off the committee, praised Alito as his testimony ended.

"I enthusiastically endorse and support Judge Alito's nomination," Chuck Hagel of Nebraska said today. Sen. Jeff Sessions, R-Ala., noted to the judge that his high school friends "predicted you would serve on the Supreme Court one day, and I think that's going to turn out to be a good prediction."

Chances of a nomination-crippling filibuster seemed to dim as the day went on, with two members of the "Gang of 14" _ centrist senators who brokered a deal last year to avoid a filibuster showdown over judges _ saying Alito's nomination does not deserve one.

Sen. Ben Nelson, D-Neb., said, "So far I have seen nothing during my interview with the nominee, the background materials that have been produced or through the committee process that I would consider a disqualifying issue against Judge Alito."

Alito offered words of respect for O'Connor, the woman he would replace. "She has been known for her meticulous devotion to the facts of the particular cases that come before her and her belief that each case needs to be decided on its complex facts," Alito said.

Democrats argue that Alito, in 15 years as an appellate judge, has built a conservative record that foretells his Supreme Court stance. But they face an uphill battle in finding enough votes to filibuster his nomination _ the only way they can stop him.

It takes 41 votes to sustain a filibuster, and there are 44 Democrats and one Democratic-leaning independent.

"We can only afford to lose five senators favoring Judge Alito before a filibuster is impossible," said Dick Durbin of Illinois, the Senate's No. 2 Democrat. "It's a very tight margin, and I'm not going to presume one way or the other whether my colleagues are even interested in it."

Added Reid: "We have not ruled out extended debate. We haven't ruled it in."

Several committee Democrats made it clear they were not inclined to vote for Alito, including Edward Kennedy of Massachusetts and Charles Schumer of New York.

After four days of hearings, there are "even more questions about Judge Alito's commitment to the fairness and equality for all," Kennedy said.

The Democrats repeatedly attacked Alito's decisions as a judge on the 3rd U.S. Circuit Court of Appeals and his writings while a lawyer for the Reagan administration _ including a 1985 statement saying the Constitution did not protect the right to an abortion _ and they highlighted his membership in an organization that discouraged the admission of women and minorities at Princeton University.

"The evidence before us makes it hard for us to vote yes," said Schumer, head of the Democratic Senatorial Campaign Committee.

One of the Democrats who voted for John Roberts' confirmation as chief justice did not sound positive about Alito. "He has not been clear that he would serve to protect all Americans' rights," said Sen. Patrick Leahy of Vermont, the ranking Judiciary Democrat.

Democrats peppered Alito about right-to-die cases, presidential authority, affirmative action and ethics on Day 4 of the hearings _ and elicited no more personal observations on such issues than they had in previous sessions.

Alito brushed aside Schumer's attempt to get his opinion of a proposal to deny citizenship to U.S.-born children of illegal immigrants.

"I need to apply the same standard that previous nominees have applied, and that's no hints and no previews. I can't opine on them here off the cuff," Alito said.

After his testimony, Alito received a supportive telephone call from President Bush, who was visiting hurricane-damaged areas along the Gulf Coast. "I'm proud of the way you handled it," Bush told Alito, according to White House press secretary Scott McClellan.